The overall objective of this research is to extract tumor associated antigens from both antigen-antibody complexes present in the serum and from the methylcholanthrene induced sarcomas of inbred mice. Protein obtained from chemical extraction procedures will be purified by gel filtration, ion exchange chromatography, reverse ammonium sulfate gradients, and subjected to isoelectric focusing. Antigens will be identified by a humoral cytotoxicity assay and by specific lymphocyte stimulation tests. The antigens will then be studied to determine their physical and biological properties. BIBLIOGRAPHIC REFERENCES: Burk, M. W., Yu, S., Ristow, S. S. and McKhann, C. F.: Refractoriness of lymph node cells from tumor bearing animals. Int. J. Cancer 15:99-108, 1975. Burk, M. W., Ristow, S. S., Yu, S. and McKhann, C. F.: Lymphocyte stimulation as means for monitoring the purification of tumor associated antigens. Federation Proceedings 30:1042, 1975.